Soundex calculation

After a fixed system each surname is coded into a combination of one letter and 3 numbers. This letter/number combination is the so-called Soundex code. Many US archives are organized and worked satisfactorily after the Soundex system. The similarity between original names and the "Anglicize" names is reconstructed by the Soundex system.

The Soundex procedure

1. The code consists of the initial at the beginning of the surname and 3 numbers.
2. For the determination of the 3 numbers all letters are replaced by the following numbers:
• 1 = B P F V
• 2 = C S K G J Q X Z
• 3 = D T
• 4 = L
• 5 = M N
• 6 = R
3. The vowels (A E I O U Y) are ignored, likewise the letters (H W Ä Ö Ü).
4. Each double letter is coded as 1 letter.
5. Credit 2 letters, which stand directly next to each other, the same code number, then both letters are coded as 1.
6. Credit 2 letters, which are through one of the ignored letters (A E I O U Y Ä Ö Ü) from each other separated, the same code number, then both letters are coded.
7. Credit 2 letters, which are through one of the ignored letters (H W) from each other separated, the same code number, then both letters are coded as 1.
   If this rule is used, then one receives a Soundex dialect.
8. The remaining numbers, from left to the right read, are built up to a block with 3 numbers. If numbers remain, then these are ignored. If less than 3 numbers are present, then with zeros one fills up.
9. If the initial letter of the surname one he ignored letter (Ä Ö Ü) is, then this is dissolved.
• Ä becomes A
• Ö becomes O
• Ü becomes U
10. If a prefix (of, van, de, di, le, to, ...) is contained in the surname, then the surname should be coded once also and once without prefix.
11. Mac and Mc do not become as additives, but when part of the surname treats.